Although it has won all the elections since democracy was restored in 1989, the Concertacion coalition in Chile has received a different vote share in presidential and parliamentary elections held concurrently. Unlike 1998 and 1993, in 2005 the congressional Concertacion candidates received more votes than the Concertacion presidential candidate. This article analyzes the extent to which the leftwing militancy of the Concertacion presidential candidate deterred moderate Concertacion voters from supporting the coalition's presidential candidate. There is evidence of that being the case. The bigger the vote share for Concertacion congressional candidates from the moderate coalition party, the larger the vote share difference between the Concertacion congressional and presidential candidates.